I am detoxing from methadone, from 75 mg down to 2.5 over 8 months and then I jumped off 5 days at 2.5 today is day 4 clean. Is the worst over?

A few more days. The last bit of Methadone can take a week to clear.
Should be. There may be several weeks of residual symptoms, but they should be milder than those you have already had - sweats, mild muscle and joint pain, occasional diarrhea and abdominal cramping etc. The symptoms can be treated with ibuprofen, pepto bismol, Imodium (loperamide) and especially Clonidine (0.05- 0.1 mg) which requires a prescription. Get lots of support! counseling is helpful to stay clean!